Multifilament lamp



Aug. 13, 1946. J. H. HOMRIGHOUS I 8 I MULTIFILAMENT LAMP Original FiledAug. 22. 1942 FIGI IN V EN TOR.

Patented Aug. 13, 1946 UNITED STATES PATENT OFFICE Divided and thisapplication November 1, 1943, Serial No. 508,453

13 Claims. 1

This application is a division of application Serial Number 455,747,filed August 22, 1942.

This invention relates in general to improve ments in electric lamps,and more particularly to lamps having a plurality of heating units orfilaments.

One of the main objects of this invention is to provide means forprolonging the useful life of electric lamp bulbs.

Another object of this invention is the provision of switching mechanisminside the evacuated envelope for automatically changing the filamentsor the heating units when one is burned out.

Several multi filament lamps have been devised, but in none of these isthe switching mechanism rotatably mounted in the evacuated bulb andcontrolled by bimetallic strips or member supported inside the tubewhich are flexed into contact when a filament is disrupted.

These and other objects and. advantages will be apparent from thefollowing detailed description, reference being had to the accompanyingdrawing in which:

Figure l is a side elevation partially in section of an illuminatingbulb with filament switching mechanism.

Figure 2 is a top detail view of the rotary switching mechanism inFigure 1.

Figure 3 is a detail view of mechanism taken on line 33 in Figure 1.

Figure 4 is-a detail end view of rotary switch mechanism taken in thedirection of the arrow 4 in Figure 2 including fragmentary portions ofbrush and upport.

Figure 5 is a schematic of the circuit used with the electric lamp.

In the drawing the reference numeral l represents a bulb or tube brokenaway to show the filament or heating unit switching mechanism on theinside of the evacuated bulb. In the center of this bulb is a hollowstem 4 extending upward from the base and having two ceramic disks 5 and6 pivotally mounted near its upper extremity. The disk 5 has two pins 1and 8 secured thereto for supporting one end of the filaments or heatingunits 9 and ID. The pins 1 and 8 are connected together by the bar I lThe disk 6 mounted on the opposite side of the stem 4 also has two pinsI2 and I3 shown in Figure 2 for supporting the other ends of the heatingor lighting units 9 and III. A stabilizing bar i4 is securely fastenedto the disks 5 and 6 so that they will rotate together. The disks arelimited in their travel by the pin l5 engaging the elongated slot in thelower rim of the disk 5. The disks Sand 6 are at first held in theposition shown in Figure l by the combination of the link l6 secured tothe stabilizing bar M with a fuse metal link connector ll, reference toFigure 4, joining it with the bar l3 which in turn is secured to theceramic or porcelain plate IS. The spring 28 secured to the disk 6 andto the plate I9 is for rotating the disks 5 and. 6 in a clockwisedirection when the fuse link ii is broken.

The porcelain plate I9 near the bottom of the bulb has two bimetalicstrips 2| and 22 rigidly secured thereto and having their uppercontacting extremitie 23 and 24 extending in quadrants about the stem 4shown in Figure 3. These movable members or bimetallic strips areprovided with coil of resistance wire 25 and 25 to heat the bimetal tocause them to flex in a counter clockwise direction. The plate is alsoprovided with a contact spring 2? for contacting the pins 12 and I3.

The operation of the switching mechanism shown in Figures 1 to 4 is asfollows, reference being had to Figure 5. The source of current supplymay be connected through conductor 23, link l6, coil 26, connecting barll, pin 7, heating unit 9, pin l2, wiping contact spring 21, andconductor 29, leading to the source of power supply. The heating unit 9in serie with coil 25 will now be energized in multiple with the heatingcoil 25.

The heating coil 25 and 26 will cause the bimetallic strips 2! and 22 toflex in a counter clockwise direction. However, should the heating unit9 burn out Or open the circuit through the coil 26 the bimetallic strip22 would return to normal position, to contact the strip 2|, thusclosing a circuit momentarily through the fuse link i1, bar l8, spring22, contacts 24 and 23, strip 2! and conductor 29. This circuit willcause the fuse link ii to fuse or melt thu allowing the disks 5 and 6 tobe rotated by the spring 26 to place the heating unit Ii] across theconductors 28 and 29.

The embodiments of the invention which have been given herein areillustrations of how the various features may be accomplished andof theprinciples involved. It is to be understood that the invention containedherein is capable of embodiment in many other forms and adaptations,without departing from the spirit of the invention and the scope of theappended claims.

Having thu described my invention, I claim:

1. In an electric lamp, a pair of filaments. a current supply circuit,spring controlled rotatable mechanism for supporting said filaments,said mechanism arranged to connect any one of said filaments inpredetermined position to said current supply circuit, a fusable elementfor holding said mechanism under tension of said spring to maintain oneof aid filaments in said position, an automatic switch comprising a pairof spaced bimetallic contact members adapted to be actuated into contactto connect said element to said supply circuit, and means for closingsaid contact member responsive to the disruption of the connectedfilament to open said link thereby releasins said mechanism to rotateanother one of said filaments to said predetermined position, and toconnect said other filament to the said current supply circuit.

2. In an article of manufacture, a plurality of electrical circuitelements, switching mechanism for controlling the energizing circuit forsaid elements, a fusible link for holding said mechanism under tension,an automatic switch comp-rising a first bimetallic strip and a secondbimetallic strip each having portion disposed with a relativelyenergized coil for moving away from said second strip, and sensitive tothe disruption of the energizing circuit in said first element formoving into engagement with said second strip, thereby disrupting saidlink to release the said mechanism for energizing a second one of saidcircuit ele ments.

3. In an evacuated bulb a filament supported in said bulb, a switchcomprising a pair of spaced bimetallic members adapted to be actuatedinto contact, a heating coil for each of said members with one of thecoils being in series with said filament, said members sensitive totheir energized coils for flexing in the same direction to maintainseparation, whereby the deenergization of said one coil causes saidmembers to contact.

4. In an article of manufacture first and second load elements, a quickmake switching mechanism for controlling an energizing circuit for saidelements, a fusible link device for holding said mechanism under tensionto maintain said first element in said energization circuit, anautomatic switch comprising a pair of spaced bimetallic contact membersadapted to be actuated into contact, a heating coil for each of saidmembers with one of the coils in series with said first element, saidmembers sensitive to the energization of said coils for flexing in thesame direction to maintain separation, whereby the deenergization ofsaid one coil responsive to the disruption of said first elementcompletes an energizing circuit through said members and said fusiblelink device to cause said mechanism in a quick movement to connect saidsecond element in said energizing circuit.

5. In an evacuated envelope, a pair of spaced bimetallic contact memberssupported in said envelope adapted to be actuated into contact, aheating coil for each of said members, said members sensitive to theirenergized coils for flexing in the same direction to maintainseparation, whereby the deenergization of one of said coils causes saidmembers to come into contact.

6. In an evacuated bulb, a first bimetallic men her and a secondbimetallic member, said members having portions with a relatively smallspace therebetween and adapted to be actuated into contact, a heatingcoil for each of the said members, said members sensitive to theirenergized coils for flexing in the same direction to maintainseparation, whereby the deenergization of said coil associated with saidfirst member causes its associated portion to contact the portion assciated with said second members.

7. An evacuated envelope, a pair of filaments supported in saidenvelope, a current supply circuit, switching mechanism arranged toconnect the current supply circuit through said filaments in succession,a fusible link for holding said mechanism under spring tension toconnect one of said filaments to said current supply circuit, aswitching device comprising a pair of spaced bimetallic contact stripssupported in said envelope and adapted to be actuated into contact toclose a circuit from said current supply circuit through said link, oneof said strips responsive to a disrupted filament for closing saidcontact s rips to disrupt said link, thereby actuating said mechanism toconnect another one of said filaments to the said current supplycircuit.

8. In an evacuated envelope, a pair of filaments, switching mechanismfor controlling the energizing circuits for said filaments, a currentcontrolled holding device for maintaining said mechanism under tensionto energize a first one of said filaments, a bimetallic switchcomprising a flexible first member and a flexible second mem ber, saidmembers adapted to be actuated into contact to close a circuit throughsaid device, a coil for said first member connected in serie with afirst one of said filaments, said first member sensitive to itsenergized coil for maintaining separation of said members and sensitiveto the disruption of the said first filament connected in series withits coil for engaging said second member to close a current path throughsaid holding device, thereby actuating the said switching mechanism forenergizing another one of said filaments.

9. In an electric lamp, a pair of filaments, each provided with aterminal contact, mechanism rotatably mounted for supporting saidfilaments including said contacts, a brush adapted to engage saidcontacts in succession, a fuse link for holding said mechanism undertension to maintain said brush in engagement with a first one of saidfilaments, and mean-s for disrupting said fuse link, thereby rotatingthe said mechanism to establish a current through a second one of saidfilaments.

10. In an electric lamp, a plurality of filaments, each provided with acontact, a brush, rotatable mechanism for connecting said brush to saidcontacts in succession, a fuse link for said mechanism to hold one ofsaid contacts in engagement with said brush, a source of current supply,a switch device for closing a circuit through said fuse link to thesource of current supply to disrupt the said fuse link, thereby rotatingsaid mechanism for connecting said brush with another one of saidcontacts.

11. In an article of manufacture, a plurality of circuit elements,switching mechanism pivotally mounted for controlling the energizingcircuit for said elements, a fusible link for holding said mechanismunder tension, an automatic switch comprising a flexible first contactmember and a flexible second contact member disposed with a relativelynarrow space therebetween and adapted to be actuated into contact toclose an energizing circuit through said link, means for moving saidfirst member away from said second member, and

for moving said second member toward said first member responsive to theenergization of one of said elements, and means for moving said firstmember into engagement with said second member responsive to thedisruption of the said energized element to rotate said mechanism forenergizing another one of said elements.

12. In an evacuated envelope, a pair of filaments, switching mechanismfor controlling the energizing circuit for said filaments, an automaticSwitch comprising a pair of spaced bimetallic strips adapted to beactuated into contact, a heating coil for each of said strips, said coilfor said first strip connected in series with one of said filaments,said strips sensitive to heat developed by their energized coils forfleXing in same direction to maintain separation, said first stripsensitive to the disruption of the said filament connected in serieswith its coil for moving into engagement with said strip to therebyactuate the said switching mechanism for energizing another one of saidfilaments.

13. In an electrical lamp, a pair of filaments, each provided withterminal contact, a source of current, switching mechanism rotatablymounted for supporting said filaments including said contacts, a brushfor connecting the source of cur rent to said contacts in succession, afuse link for holding said mechanism under tension to maintain aid brushin engagement with one of said contacts, an automatic switch comprisingfirst and second bimetallic strips adapted to close a circuit from thesource of current through said link, a heating coil for the firstcontact strip connected in parallel to the source of current, said firststrip being sensitive to its energized coil for flexing toward thesecond strip, another heating coil for the second strip connected inseries with one of the said filaments, said second strip being sensitiveto its energized coil for flexing away from the first strip, and upondeener ization of its coil for flexing toward the first strip to close acircuit through the fuse link to the source of current, therebydisrupting the said link to rotate said mechanism for connecting'asecond one of said contacts to the source of current.

JOHN H. HOMRIGHOUS.

